Autism prevalence may be higher than previously thought

Submitted by bobb on Tue, 10/05/2011 - 7:06pm

Jessica Hamzelou, reporter

One in every 38 children may have an autism spectrum disorder - more than double the current US estimate. The latest research in a South Korean population suggests that by overlooking children attending regular schools, previous reports wildly underestimated the true prevalence of the disorder.

Autism spectrum disorders, or ASDs, include autism and Asperger's syndrome, and are developmental disorders characterised by social, communication and behavioural problems. Young Shin Kim and her colleagues at Yale University's Child Study Center in Connecticut set out to assess the prevalence of ASDs in over 50,000 seven- to twelve-year-olds in a South Korean community.

The group first screened the schoolchildren through questionnaires sent to their parents and teachers. Those that screened positive for ASD were then individually assessed by two child psychiatrists.

Based on this sample, Kim's team estimate that around 2.64 per cent of the South Korean population has ASD - that's one child in every 38. The new estimate is over double the existing estimate of the US rate, which the Center for Disease Control and Prevention puts at one in 110.

The finding doesn't necessarily mean that ASDs are more common in South Korea, though - Kim's team reckon that researchers might find similarly high rates in other countries were they to investigate larger, non-clinical populations. In an interview with the New York Times, Kim said:

From the get-go we had the feeling that we would find a higher prevalence than other studies because we were looking at an understudied population: children in regular schools

Geraldine Dawson of autism advocacy group Autism Speaks, which funded the study, said:

These findings suggest that ASD is under-diagnosed and under-reported and that rigorous screening and comprehensive population studies may be necessary to produce accurate ASD prevalence estimates

source: American Journal of Psychiatry, DOI:10.1176/appi.ajp.2011.10101532